He Wenhua

Emulation and Experimental Study of Drum Dynamometer for Simulating the Vehicle's Road Braking

The current drum dynamometer cannot test the vehicle’s dynamic braking performance. The equivalent moment of inertia test method was put forward to simulate the vehicle’s the road braking. A variable mass inertia wheel, whose moment of inertia was equal to the vehicle’s equivalent moment of inertia, was introduced in the design of drum brake unit. The prototype was made to observe the vehicle braking performance. Compared with the emulation in Matlab, the results show that the test method is applicable to the vehicle with different mass and at various speeds and the drum brake unit can reflect the vehicle road braking performance accurately.

Research on Repeatability of Vehicle Mass Analysis System

According to the specific requirements of national standards on transient emission measurement system, an emission measurement system with VMAS is constructed. The components and theory of VMAS are introduced. The system’s repeatability is discussed based on test results. Then the possibility and importance are discussed about adoption the VMAS testing method for emission inspection of in-use petrol vehicles in China.